Gas turbines are now widely used and have many applications including, for example, in powering air travel, in powering sea travel and in electricity generation.
The design of gas turbines is an extremely complex task as there are many competing demands that need to be balanced and met. For example, gas turbines used for powering travel may be designed to be light but also need to maintain an acceptable level of efficiency.
Other demands on the gas turbine, such as level of emissions and noise levels must also be considered. Furthermore, the effect of changing one part of a gas turbine on every other part of the gas turbine must also be considered.
The stability/operability of the gas turbine must also be considered across the entire range of operating speeds of the gas turbine. Gas turbines are designed for a particular speed of operation, the design point of the gas turbine, however, they must also operate safely away from the design point. For example, the gas turbine must have acceptable stability margins when running at low speeds during start up of the gas turbine and also at speeds higher than the design point of the gas turbine.